lavu: check that assert level is defined

fix warning

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavutil/common.h

@@ -97,7 +97,7 @@ av_const int av_log2_16bit(unsigned v);
  */
 static av_always_inline av_const int av_clip_c(int a, int amin, int amax)
 {
-#if defined(HAVE_AV_CONFIG_H) && ASSERT_LEVEL >= 2
+#if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
     if (amin > amax) abort();
 #endif
     if      (a < amin) return amin;
@@ -114,7 +114,7 @@ static av_always_inline av_const int av_clip_c(int a, int amin, int amax)
  */
 static av_always_inline av_const int64_t av_clip64_c(int64_t a, int64_t amin, int64_t amax)
 {
-#if defined(HAVE_AV_CONFIG_H) && ASSERT_LEVEL >= 2
+#if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
     if (amin > amax) abort();
 #endif
     if      (a < amin) return amin;
@@ -222,7 +222,7 @@ static av_always_inline int av_sat_dadd32_c(int a, int b)
  */
 static av_always_inline av_const float av_clipf_c(float a, float amin, float amax)
 {
-#if defined(HAVE_AV_CONFIG_H) && ASSERT_LEVEL >= 2
+#if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
     if (amin > amax) abort();
 #endif
     if      (a < amin) return amin;